Case IH 5109-09 - DEC – DEC: CAN VB2 VCM transmission message abnormal update rate

Expected transmission data messages broadcasted by the Vehicle Control Module (VCM) over the CAN VB2 network are either missing, timing out, or being received at an abnormal frequency.

• MAGNUM AFS Connect
• Case IH Magnum AFS Connect
• Magnum 180 AFS Connect
• Magnum 200 AFS Connect
• Magnum 220 AFS Connect
• Magnum 240 AFS Connect
• Magnum 250 AFS Connect
• Magnum 280 AFS Connect
• Magnum 310 AFS Connect
• Magnum 340 AFS Connect
• Magnum 380 AFS Connect
• Magnum 400 AFS Connect

1. 1

   Use the CNH Electronic Service Tool (EST) to check if the VCM is online and communicating, and check for bus-wide network crashes.

2. 2

   With the tractor powered off and battery disconnected, measure the resistance across the CAN High and CAN Low pins on the VB2 network (should be approximately 60 ohms).

3. 3

   Inspect the CAN VB2 wiring harness between the VCM and the DEC for chafed wires, loose pins, or moisture intrusion at the connectors.

4. 4

   Check the software versions of the DEC and VCM modules for outdated software.

1. 1

   Power Cycle

   Perform a complete key-off power cycle. Wait for the displays and modules to power down completely, then turn the key back on to allow the VCM and DEC to fully reboot and attempt to re-establish CAN messaging.

2. 2

   Isolate Faulty Modules

   If the CAN bus is overloaded or crashing (which can throw the tractor into park), disconnect modules on the VB2 network one by one (such as hydraulic controllers) until the CAN VB2 network stabilizes and the update rate returns to normal. The last module disconnected before stabilization is the culprit.

3. 3

   Repair Wiring

   If the resistance test or visual inspection reveals faults in the CAN VB2 harness, repair the damaged wiring or replace the affected harness section.

4. 4

   Update Software

   If the wiring is intact, flash the DEC and VCM with the latest software using the CNH EST diagnostic tool.

5. 5

   Replace Module

   If the wiring is verified, software is up to date, and the VCM still fails to broadcast transmission messages at the correct rate, replace the VCM or DEC module as dictated by your isolation testing.